Investigators have busted an international child pornography ring that remained undetected for 12 years by using data encryption technology that one federal prosecutor said Thursday was the best he'd seen in more than 20 years on the job.

A total of 11 men from Indiana, Alabama, California, Florida, New York, Texas, and Virginia have been convicted or are in custody, prosecutors said at a news conference in Indianapolis, where the case was filed in federal court. They are charged with sexually exploiting minors.

Ring members have been charged or are under investigation in Canada, Switzerland and other countries, prosecutors said, although they didn't say how many foreign suspects.

Nearly 100 children, most of them boys who ranged from toddlers to teens, were exploited by the ring, prosecutors said.

"These defendants engaged in an operation that had one purpose and one purpose only, to promote the abuse and exploitation of our children," U.S. Attorney Joe Hogsett said.

Members of the ring mostly traded pornography instead of producing it, but at least four members allegedly conspired to produce new videos and images of boys engaging in sex, which then could be distributed to other members of the group, prosecutors said.

One of the defendants, 42-year-old John Rex Powell, of Fort Myers, Fla., is awaiting trial in a separate child porn case involving two Australians accused of making their adopted son sexually available to men around the world. Powell is charged with the sexual exploitation of children and a conspiracy count in that case.

Powell's involvement in both schemes was key to dismantling the child porn ring described Thursday, Hogsett said.

The ring began operating sometime in 2000 and was shut down in April 2012, but the investigation remained sealed until Thursday, Assistant U.S. Attorney Steve DeBrota said.

U.S. postal inspectors investigating a foreign company selling videotapes were led to individuals in Idaho and Pennsylvania, then to two Indiana men, 61-year-old John Richard Edwards, of Indianapolis, and 44-year-old Thomas Vaughn, of Anderson.

Edwards pleaded guilty a year ago to engaging in a child pornography enterprise in connection with the ring and was sentenced to 17½ years in prison.

The ring was able to operate for so long because of data encryption technology that DeBrota, who specializes in Internet cases, called the best he's seen in his more than 20 years as a prosecutor.

"We were able to identify a previously unidentified super-secret group which we allege trafficked in child pornography in vast quantities over a 12-year period of time," DeBrota said.

The largest individual collection of child pornography in the ring had about 18 terabytes, or 18 trillion bytes, of images, DeBrota said.

Some ring members were information technology professionals, and the more tech-savvy members of the group coached the less tech-savvy in the secrecy needed to evade detection, Assistant U.S. Attorney Brant Cook said. He said members communicated through social media and in chat rooms to encourage one another to collect, traffic and produce more child porn